Paul’s conclusion (1 Cor 10:23) was on foods sacrificed to objects (idols) that mean nothing (worthless) because it seems he was addressing a specific question and he based his conclusion on:
Nothing does not mean worthless. If the idol means nothing to me, meat offered to it means nothing to me. Simple.
Psalms 115: 4 But their idols are silver and gold, made by human hands.
5They have mouths, but cannot speak, eyes, but cannot see.
6They have ears, but cannot hear, noses, but cannot smell.
7They have hands, but cannot feel, feet, but cannot walk, nor can they utter a sound with their throats.
8Those who make them will be like them, and so will all who trust in them.
This curse pertains to just the people that believe the idols mean something.
Jeremiah 10:5
"Like a scarecrow in a cucumber field are they, And they cannot speak; They must be carried, Because they cannot walk! Do not fear them, For they can do no harm, Nor can they do any good."
That’s why Paul said “For the earth is the Lord's, and the fulness thereof”
Exactly.
BUT
Paul’s warning in 1 Cor 10:14-21 which as a side note (not the main issue to be addressed) stands and was based on:
Acts 15:28 It seemed good to the Holy Spirit and to us not to burden you with anything beyond these essential requirements: 29You must abstain from food sacrificed to idols, from blood, from the meat of strangled animals, and from sexual immorality. You will do well to avoid these things. Farewell.”
It is essential you still miss the point. You can eat this meat without defilement unless you think it defiles you or someone else.
In case you forgot, essential means essential.